Signaling system



Jan 6, 1931. H. D. BULLOCH 1,

SIGNALING SYSTEM Filed Oct. 24, 1928 INVENTOH hf L7. BULLOGH STAT SUNITE PATENT! QFFHQE HAROLD D. BULLOCK, OF FORT WORTH, TEXAS, ASSIGNORTO AMERICAN TELEPHONE AND TELEGRAPH COMPANY, A. CORPORATION OF NEW YORKsrenamne SYSTEM Application filed October 2 1, 1928. Serial No. 314,683.

guishes the present invention from systems previously proposed is meansfor operating such systems by alternating current without the use ofconstantly operating motors, batthree motors.

teries or other equipment which-requires attention or consumes powerwhile not actually in use. p

In such systems it is customary to provide means so that the callingstation may start the printer mechanisms when a message is to be sentand, stop them when the message is completed. One such system isdisclosed in Patent 1,648,974-granted to Vernam November 15, 1927. Itshould be noted,however,

that systems of this kind require a source of energy such as a generatorwhich must be running continuously so as to be available at vall timesto supply power to the printer motors. If the power required is obtainedfrom alternating current mains, such a source is of course unsuitablefor operating the printer selecting magnets so that a battery or itsequivalentmust be provided at each local station. In. either caseoperating or maintenance expense in addition to that occasioned by theactual transmission of messages is involved. 4

In accordance, therefore, with the present invention, these telegraphsets may be energized entirely from local alternating current sources byproviding alternating current mo tors for driving the distributors, theprinter mechanism and also a local, normally idle, direct currentgenerator. A relay at each station is arranged to release upon an openimpulse from the calling station to start all Direct current from thelocal generator is then available to operatethe selecting magnets andalso a second relay which shunts the motor control relay out of theline. When the message is completed,

the circuit of the second'relay is opened lo cally at each station,thereby reenergizing the motor control relay, stopping the motors andleaving the system in the proper condi tion to respond to the nextstarting impulse.

The drawing illustrates one embodiment of the invention. Each of thestations 1 and 2 connected by a line'conductor 3 is equipped withcomplete transmitting and receiving mechanisms of the start-stop type.For the sake of'simplifying the drawing, transmitting and receivingequipment is indicated only at station 1.

- The transmitting equipment comprises the transmitting distributor 4which has a brush arm 5 frictionally mounted. on a shaft 6, driven by amotor 7 and which is arranged to be stopped periodically by a releasemagnet 8. The brush arm 5 is provided with a brush for consecutivelybridging a plurality of segments With a continuous ring, the segmentsbeing connected with the contacts of the transmitter 9 which may beeither of the automatic or manual type. The receiving mechanismcomprises a receiving distributor 10 which like the transmittingdistributor L is provided with a release magnet 11 for pcriodicallyarresting the rotation of brush'arn'r 12 also frictionally mounted onthe shaft 6. The segments of the distributor 10 are con nected with theselecting magnets 13 of a receiving printer 14. Only so much of theprinter is shown as is necessary for a clear understanding of theinvention. The printer may, of course, be of any well known type, suchas that disclosed in Patent 1,623,809, granted to Pfannenstiehl April 5,1927.

Each of the stations is provided with a line relay 15 which controlsthrough its front contact the energization of the selecting magnets13upon the passage of the brush carried by the brush arm 12 over thesegments to which the selecting magnets are connected. Relay 15 throughits back contact controls the release magnet 11 of the receivingdistributor 10. In series with the line at each station is a relay 16which is arranged to control a power supply 17 in response to variationsof line current as already described.

The operation of the system with particular reference to the presentinvention will of course, in most cases be a connection to local powermains so that no power is con-' sumed until relay 16 releases.Distributor/1 and the main shaft of the printer indicated at 14 come upto speed quickly and the gen- 15 erator 21 builds up voltage so that thestation apparatus is in readiness for the trans mission of signals fromstation 2. As the generator comes up to speed current flows through thewinding of relay 26, closing contact 27 and thereby preventing the linecurrent from reenergizing relay 16 and stopping the motors when key 23'is released.

Since the apparatus at station 2 is a duplicate of that at station 1, itis obvious that the 25 motors at station 2 also will be started inresponse to the operation of key 23' and maintained in operation by therelays at that station as already described for station 1. When themessage is completed the calling station will indicate this fact bytransmitting a predetermined signal. Each station operator will thenopen the local switch 28 thereby disconnecting the power source from themotor-s and bringing them to rest. As the generator decelerates relay 26is released thereby removing the shuntfrom relay 16 and permitting theline current to open contact 22. As soon as the motors have stopped,switch 28 is reclosed so that relay 16 may again put the stationapparatus in service in response to an open impulse. i

For conveniense in illustrating the invention it has been described withreference to a particular system, but it will ,be evident that theinvention is applicable to many modifications of the specificdisclosure. For example, the drawing shows schematically a simplestart-stop system comprising a line connecting two stations; the system,however, may be of any other 'well known type and may consist of anumber of stations in a series or operating through a common exchange asin a telephone system. In'some cases, where operating conditions permit,it might be preferable to energize relay 26 by means of line current oreven to omit relay 26 altogether and add additional contacts to relay16. If either of these expedients were employed, it would, of course, benecessary to add a stop key in series with the contacts shunting relay16.

What is claimed is:

1. A control system comprising a line connecting a plurality ofstations, recording ap paratus located at.each of the stations andoperative over the line, an electric motor for supplying motive power tothe recording apparatus, an operating circuit for the motor, meansresponsive to a predetermined alteration of the normal condition of theline for closing the operating circuit, and locally energized relaymeans for maintaining the circuit independently of subsequent changes inthe condition of the line. 2. A control system comprising a lineconnecting a plurality of stations, recording apparatus having aplurality ofselecting magnets at each of the stations and operative overthe line, a source of power, a generator for supplying current to themagnets, a plurality of motors driving the apparatus and'the generator,a circuit between the power source and the motors including relay meansresponsive to a predetermined-alteration of the normal condition of theline for energizing the motors, means responsive to current from thegenerator for maintaining the circuit independently of subsequentchanges in the condition of the line, and means at each of the stationsfor stopping the motors at'that station and reconditioning the relaymeans.

3. A power supply system for printing telegraph apparatus comprising asource of power, a generator, motors driven by the source and supplyingmotive power to the apparatus and to the generator, relay means remotelycontrolled for energizing the motors, means responsiveto current fromthe generator for preventing reoperation of the relay means, and meansadjacent to the ap- 1 paratus for stopping'the motors.

4. A power supply system for printing telegraph apparatus comprising asource of alternating current, a normally deenergized source ofsignaling current, at least one motor driven from the alternatingcurrentsource for, actuating the apparatus and energizing the sourceofsignaling current, and relay means remotely controlled for energizingthe motors. I

5. A power supply system for printing telegraph apparatus comprising asource of alternating current, a normally deenergized source ofsignaling current, a plurality of motors driven from the alternatingcurrent 1 source for actuatin ,the apparatus and energizing the source 0signaling current, relay means remotely controlled for energizing themotors, means responsive to current from the source of signaling currentfor preventing the reoperation of the relay means and means adjacent tothe apparatus for stopping the motors.

In testimony.whereof, I have signed my name to this specification this17 day of 00- tober, 1928.

1 HAROLD D. BULLOCH.

